The present invention relates to the art of packaging semiconductor devices, and more particularly, to an improved silver-glass paste which is fired in an oven to securely bond semiconductor die to ceramic substrates.
Silver-glass pastes have been used in the past for attaching silicon die to ceramic substrates. One prior art silver-glass paste uses silver flakes and lead zinc borate glass frit mixed in a liquid organic vehicle. During an initial drying phase, the liquid vehicle evaporates. Upon firing in an oven, the remaining organic vehicle decomposes and the glass melts down to wet the ceramic substrate, while the silver flake sinters together. Upon cooling, the result is a bond between the silicon die and the ceramic substrate.
U.S. Pat. Nos. 3,497,774 of Hornberger et al. and 4,101,767 of Dietz et al. disclose silver-glass paste formulations for semiconductor die attachment.